Supervisory circuit for optical repeater
AssigneeNEC Corporation
InventorShuji Yamashita
Life of this patent
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Abstract
A supervisory circuit for optical repeaters has a selective decoder circuit for selecting and decoding either one of control signals for monitoring which are separated from individual transmission signals being propagated over the first channel and the second channel. When noise ascribable to a fault occurs on the first channel, a signal path connecting to the selective decoder circuit for inputting a control signal from the first channel is interrupted. Noise of this kind is detected in terms of an input signal level which does not lie in the frequency band of control signals.
Claims4
A supervisory circuit for an optical repeater, comprising:
- separating means for separating a control signal from a transmission signal, said control signal being superposed on said transmission signal being propagated over a first channel;
- detecting means responsive to said transmission signal for detecting a predetermined frequency component of noise attributed to a fault on said first channel and generating a signal indicating whether or not said noise exists on said first channel, said predetermined frequency component being different from a frequency component of said control signal;
- switching means for sending in response to said signal indicating that said noise does not exist, said control signal separated by said separating means and intercepting said control signal separated by said separating means, in response to said signal indicating that said noise exists;
- and
- selective decoding means for selecting and decoding either said control signal on said first channel fed from said switching means or another control signal fed from a second channel, depending on a combination of presence/absence of said control signals.
Dependencies are inferred from the claim text.